In this installment, we’re diving into the details of the Fox Body engine and drivetrain combo. We’ve already alluded to this Fox Body project being the first vehicle that we’ve built and campaigned in a while, so you can imagine our excitement about the engine application that will power the car. If you’ve followed along, you already know that we’re keeping things Blue Oval powered with a SPEC Racing Engines built engine combination with Engler stack injection.
When it came to the decision of what engine and transmission we wanted to utilize, it was clear that whatever we chose would need to withstand the high pressure of repeated abuse on track but also be somewhat street-able.
While capable of knocking out a quick run through the quarter mile, it’s evident this Foxbody is being built to spend the majority of it’s time dominating on the autocross and road course. To that end we wanted an engine built with those considerations in mind. Those specifications would clearly affect the camshaft, flywheel, clutch, and other areas of the build.
A call over to local Indiana engine builder SPEC Racing Engines/Scott’s Performance Engine Center led to the creation of an engine package that would be able to survive multiple 20-minute track day sessions, time and time again. Once Scott fully understood our working parameters, he got to work. Starting with a 358 C.I. Ford Racing R452 compacted graphite block, Scott selected a Sonny Bryant crankshaft, Carrillo rods and CP custom lightweight pistons for a robust combination that would serve our purpose well and have no problems repeatedly revving to 8000 RPM.
Air enters the engine via eight stack injection runners and into the aluminum cylinder heads. After the combustion the exhaust stroke sends spent fumes into a set of Ultimate Headers long tubes. The headers feature 2 5/8’’ primaries and direct spent exhaust gases through 3’’ collectors and exhaust tubing all the way in a true dual configuration.
CNC ported Ford SVO Yates C3-style aluminum cylinder heads with Xceldyne titanium valves and retainers, PSI valve springs and Jesel rockers were secured in place. Manton was called on for the 7/16” pushrods, while Brad Miller’s shoulder was tapped for lifters. In control of the valvetrain is a custom grind (ssshhhh!!!) Comp Cams tool steel cam.
All of this high-revving hardware is lubricated by a dry-sump oil system that ensures positive oil pressure no matter how much lateral acceleration the car is pulling.
All said and done, this combination yields a spicy 10.5:1 compression ratio and generates right around 800 horsepower on the engine dyno. Admittedly, this is a race motor, so 110 octane will keep things under control, minimizing any occurrence of detonation.
A triple disc Tilton clutch acts as the intermediary between the engine and the Bowler sourced Tremec TKX five-speed transmission. If you’ve ever had the pleasure of driving a TKX-equipped vehicle, they shift nicely and can reliably handle a considerable amount of torque (600 lb. ft.) and repeated high-RPM shifts.
clutch was installed which acts as the intermediary between the engine and the Bowler sourced Tremec TKX five-speed transmission. If you’ve ever had the pleasure of driving a TKX-equipped vehicle, they shift nicely and can reliably handle a considerable amount of torque.
Between the S550 rear chunk we kept things simple, opting for a standard steel one-piece driveshaft. Sure, a carbon one would be cooler, lighter, and reduce reciprocating mass, but for our purposes a steel unit with beefy u-joints will suit us just fine.
After torque transfers through the driveshaft into the rear chunk it changes direction 90 degrees and rotates a set of Driveshaft Shop custom length S550 axles, which should have no problem standing up to the task at hand. At the end of the day, we’re eager to put this engine and trans combination through its paces this season. Hopefully you end up seeing it at an event near you and area able to enjoy the sound of a high-revving V8 engine with NASCAR heritage breathing through individual throttle bodies.
As mentioned in a prior update, all of this power is transmitted through a steel one piece driveshaft and through an S550 derived Super 8.8 center section and a set of shortened S550 axles that pair with the slightly reduced track width of the Fox Body platform.
We’re excited to see how this drivetrain pairs with the suspension with our in-house developed front and rear suspension on track and look forward to reporting back with hard data from a future track day outing.
If you have any questions, feel free to ask them in the comments below! Until next time!
